I wanted to measure the rise time of the normal and fast edge pulses in a new acquired Tektronix CG5011 calibration generator. The equipment line is as follows:

Tektronix TM5006 mainframe

Tektronix CG5011 Calibration Generator

Tektronix CG5001 Calibration Generator

Tektronix/Tegam 015-0611-01 Pulse Head

HP 83480A Communications Analyzer

HP 83483A Electrical Sampling Module (20GHz)

Background: The original 015-0311-00/01 pulse head was used in combination with the CG551AP and CG5001 calibration generators. The 015-0611-00/01 pulse head is the later version used on the CG5010 and CG5011 calibration generators. The primary differences between the later 0611 and earlier 0311 are:

The 0611 has faster edge rise time of <150 ps or < 160 ps for the Tegam version
The 0311 has slower edge rise time of <200 ps
The 0611 is larger (taller) than the 0311
The 0611 made by Tegam has an SMA output connector
The 611 made by … Read More »

I recently had the opportunity to purchase one of these units, and I am thoroughly enjoying the process of checking its operation and getting to know how to use it. This unit is a laboratory grade, very accurate digitizing oscilloscope from about 1990. From the Tek Wiki entry:

Upon examining it, I found that the scope tray was loose and the tilt mechanism did not function properly. The cause for this was broken trunnion mounts on both sides of the cart as follows:

Three of the four bosses were fractured with the fracture surface indicating tensile overload. I suspect that the bolts were overtightened and the bosses fractured. Overtightening loaded the bosses in tension by trying to compress the box frame member. Unfortunately this type of polymer (some type of hard thermoplastic) is not good in tension.

Other mobile carts I have seen use cast aluminum for these trunnion mounts, which is a better choice for strength and durability. The cart I have for my 556, a 205-2 (triple wide), uses cast aluminum trunnion mounts.

I had recently the unique opportunity to acquire a complete Tektronix 556 Oscilloscope setup. This comprised the oscilloscope itself, the matching scope cart, original manual, probes and 12 plug-in units. This in itself is rare enough, but in addition, this particular scope has the optically desirable blue phosphor CRT and Tektronix C-27 Camera Bezel. This 50 MHz bandwidth oscilloscope was the state of the art when it was introduced in the mid 1960’s: Tekwiki Tek 556

This will be the first of many posts and updates as I work my way through checking and restoring this beautiful scope.

Here are some images of one 7904 mainframe with a 7A24 vertical module and a 7B92A horizontal module. The scope screen shows the pulse from an S52 pulse head; the rise time is about 850ps which translates into a bandwidth of about 412 MHz. Since the 7A24 plug-in is specified at 400 MHz, this is about right.

This is the same pulse from an S52 pulse head but using an S4 sampling head instead of the 7A24 vertical amplifier

I am doing some testing on recently acquired Tektronix 7000 series equipment. Involved in these images is a Tektronix 7904A mainframe using a 7S12 TDR/Sampler plug in with an S52 pulse generator and S4 sampling head.

The rise time on of the pulse is about 32ps which translates to a bandwidth of about 11 GHz; all this for a few hundred dollars.